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TRANSCRIPT
Towards Zero Energy Buildings
Bjarne W. Olesen, Technical University of Denmark
Per Heiselberg, Aalborg University
Outline
• 0:00 European and US actions towards ZEB (Bjarne)
• 0:12 European Definition of nZEB (Per)
• 0:17 Experience with low energy buildings (Per)
• 0:25 Energy Efficient Ventilation of Buildings (Per)
• 0:40 Energy efficient Heating and Cooling of buildings (Bjarne)
• 0:55 Q&A
European and US actions
towards ZEB
• Building codes and standards
• Energy performance directive
• Renewable energy requirements
• Requirements to products and components
Role of the Building Sector ¨’
40 % of EU’s energy use
36 % of EU’s CO2 emissions
Cost-effective energy savings potential: ~30 % by
2020
9 % of GDP, 8 % of employment and
€2 trillion annual turnover
4/12
Comprehensive set of legislation to enhance energy efficiency
.Directive for the taxation of energy products and electricity
. Energy end-use efficiency and energy services Directive Services
.Directive on the promotion of cogeneration Generation
Buildings . Energy performance of buildings Directive
(EPBD)
.Directive establishing a framework for the setting of eco-design requirements for energy-using products (implementing directives for e.g. boilers, refrigerators, freezers and ballasts for fluorescent lighting
Eco-Design
.Directives for labelling of e.g. electric ovens, air-conditioners, refrigerators and other domestic appliances . Regulation of Energy Star labelling for office equipment
Product
Labelling
Taxation 5/14
The 20-20-20 EU policy by 2020
Greenhouse
gas levels
Energy
consumption
Renewables in
energy mix
-20% -20%
100%
20%
8,5%
Required reductions in
energy use in European
countries
2020 in relation to 2005
Directive 2009/28/EC (Renewable Energy Directive 2009) of the
European Parliament and of the Council of 23 April 2009 on the
promotion of the use of energy from renewable sources
National overall targets for the share of energy from renewable
sources in gross final consumption of energy in 2020
• Hungary 4,3 % 13 %
• Malta 0,0 % 10 %
• Netherlands 2,4 % 14 %
• Austria 23,3 % 34 %
• Poland 7,2 % 15 %
• Portugal 20,5 % 31 %
• Romania 17,8 % 24 %
• Slovenia 16,0 % 25 %
• Slovak Republic6,7 %14 %
• Finland 28,5 % 38 %
• Sweden 39,8 % 49 %
• United Kingdom 1,3 % 15 %
Belgium 2,2 13 %
Bulgaria 9,4 16 %
Czech Republic 6,1 13 %
Denmark 17,0 30 %
Germany 5,8 18 %
Estonia 18,0 25 %
Ireland 3,1 16 %
Greece 6,9 18 %
Spain 8,7 20 %
France 10,3 23 %
Italy 5,2 17 %
Cyprus 2,9 13 %
Latvia 32,6 40 %
Lithuania 15,0 23 %
Luxembourg 0,9 11 %
2005-2020 2005-2020
Part of renewable energy sources
(wind and bio-fuel) in Denmark
Comprehensive set of legislation to enhance energy efficiency
.Directive for the taxation of energy products and electricity
. Energy end-use efficiency and energy services Directive Services
.Directive on the promotion of cogeneration Generation
Buildings . Energy performance of buildings Directive
(EPBD)
.Directive establishing a framework for the setting of eco-design requirements for energy-using products (implementing directives for e.g. boilers, refrigerators, freezers and ballasts for fluorescent lighting
Eco-Design
.Directives for labelling of e.g. electric ovens, air-conditioners, refrigerators and other domestic appliances . Regulation of Energy Star labelling for office equipment
Product
Labelling
Taxation 11/14
Energy Performance of Buildings Directive – EPBD (2002/91/EC)
Requirements - for Member States to specify and implement:
An integrated methodology to rate the energy performance of
buildings
Minimum energy performance standards for new and for
existing buildings that undergo major renovation
Energy performance certificates for buildings
Regular inspections of boilers and
air-conditioning systems
12/14
The effect og
building
regulations
US developments towards ZEB
• Often driven by private organization like
ASHRAE
• Very different from state to state
• Several states are reffering to ASHRAE standard
90.1
• California has the most strict criteria in their
California Building Standards Code ,Title 24
• DOE (department of Energy) want to have a
national definition of ZEB
ASHRAE’s contribution to ZEB
• Standards
• Handbooks
• Advange Energy Design Guides
Major Standards
under Review/Revision
ASHRAE-Energy Performance
Standards
• ANSI/ASHRAE/IES Standard 90.1-2013 -- Energy
Standard for Buildings Except Low-Rise Residential
Buildings
• ANSI/ASHRAE Standard 90.2-2007 - Energy Efficient
Design of Low-Rise Residential Buildings
• ANSI/ASHRAE/IES 100-2015 - Standard 100-2006.
Energy Efficiency in Existing Buildings
• ANSI/ASHRAE/USGBC/IES/ICC 189.1-2014 Standard
for the Design of High-Performance, Green Buildings
Except Low-Rise Residential Buildings
ANSI/ASHRAE/IES Standard 90.1-2013 -- Energy
Standard for Buildings Except Residential Buildings
20
Source: Pacific Northwest National Laboratory
Advanced Energy Design Guides:
522,000 in circulation
Four 50% AEDGs Being Implemented
•50% Grocery Stores
– Quick Serve Restaurants
– Places of Assembly
•Under Discussion
•Net Zero – K-12 Schools (2)
– Quick Serve Restaurants
– Places of Assembly
– “Net Zero Ready” Guidance
www.ashrae.org/freeaedg
Building Energy Quotient
• Free submissions offered to qualified ASHRAE
members until Nov. 30, 2014
• Expanded to allow submissions by professional
engineers in addition to ASHRAE-Certified
Building Energy Assessment Professional
(BEAP) or Building Energy Modeling
Professional (BEMP)
• Updated In Operation Workbook with more
consistent, streamlined procedures
• EPA-Energy Star rating???
ZEB Concept
Over the course of a year, if
the on-site renewable energy
produced ≥ the energy
consumed within the
boundary, it is considered a
ZEB
23
Site Energy (n)ZEB
A building where the actual annual delivered energy ≤ on-site
renewable exported energy as measured at the site.
24
Source Energy (n)ZEB
A building where the actual annual
delivered energy ≤ on-site renewable
exported energy as measured at the
building site and converted to source
energy.
25
Zero Energy Cost Building
A building where the actual annual energy costs are zero.
26
(Net) Zero Energy Building (ZEB) Definition
An energy-efficient building, where on a
source energy basis, the actual annual
delivered energy is less than or equal to the
on-site renewable exported energy.
27
EUROPEAN DEFINITION OF NZEB
Per Heiselberg
TIMELINE OF KEY EU LEGISLATION AFFECTING
ENERGY USE IN BUILDINGS
THE EU- DIRECTIVE ON ENERGY
PERFORMANCE OF BUILDINGS 2002
(IMPLEMENTED IN DK IN 2006)
THE GENERAL FRAMEWORK FOR A
METHODOLOGY OF CALCULATION OF THE
INTEGRATED ENERGY PERFORMANCE OF
BUILDINGS;
• The application of minimum requirements on the energy
performance of new buildings;
• The application of minimum requirements on the energy
performance of large existing buildings that are subject to
major renovation;
• Energy certification of buildings
• Regular inspection of boilers and of air-conditioning
systems in buildings and in addition an assessment of
the heating installation in which the boilers are more than
15 years old.
EU DIRECTIVE ON THE ENERGY PERFORMANCE
OF BUILDINGS
Def in i t ion
• The amount of energy actually consumed or estimated
to meet the different needs associated with a
standardised use of the building, which may include,
inter alia, heating, hot water heating, cooling,
ventilation and lighting.
• This amount shall be reflected in one or more numeric
indicators which have been calculated, taking into
account insulation, technical and installation
characteristics, design and positioning in relation to
climatic aspects, solar exposure and influence of
neighbouring structures, own-energy generation and
other factors, including indoor climate, that influence
the energy demand
ENERGY PERFORMANCE REQUIREMENTS TO BE SET WITH A V IEW
TO ACHIEVING COST OPTIMAL LEVELS USING A COMPARATIVE
METHODOLOGY FRAMEWORK
• Cost optimal performance is defined as the energy performance in terms of
primary energy leading to minimum life cycle cost.
EDBP RECAST ESTABLISHED THE TARGET OF NEARLY ZERO
ENERGY BUILDINGS ( NZEB) FOR ALL NEW BUILDINGS
• By 31 dec 2020, all new buildings are nearly zero energy buildings
• After 31 dec 2018, public authorities that occupy and own a new building shall
ensure that the buildings is a nearly zero energy building
EPBD RECAST
- TARGETS FOR COST OPTIMAL AND NZEB
EDBP RECAST
-DEFINITION OF NEARLY ZERO ENERGY
BUILDINGS
I n the d i rec t i ve “near ly ze ro energy bu i l d ings ” means a bu i l d ing tha t
has a ve ry h igh energy energy per fo rmance .
The near l y ze ro o r ve ry l ow amount o f energy requ i red shou ld be
covered to a ve ry s ign i f i can t ex ten t by energy f rom renewab le sources ,
i nc lud ing energy f rom renewab le sources p roduced on -s i te o r nearby
De f in i t i on o f “a ve ry h igh energy per fo rmance ” and “s ign i f i can t ex ten t
o f renewab les ” a re de f i ned by member s ta tes
NEARLY ZERO ENERGY BUILDING DEFINITION
NEARLY ZERO ENERGY
BUILDING DEFINIT ION SHALL
BE BASED ON DELIVERED
AND EXPORTED ENERGY
ACCORDING TO EPBD
RECAST AND EN 15603 :2008
ENERGY USE IN THE
BUILDINGS INCLUDES
ENERGY USED FOR
HEATING, COOLING,
VENTILATION, HOT WATER,
L IGHTING AND APPLIANCES.
THIS IS NEEDED FOR
CALCULATION OF EXPORTED
ENERGY OR TO ANALYZE
LOAD MATCHING AND GRID
INTERACTION OF NZEB
Total energy useof the building
Delivered energy
Exported energy
Building site = system boundary of delivered and exported energy
System boundary of building technical systems
BUILDING
NEEDSHeatingCooling
VentilationDHW
LightingAppliances
Building site boundary = system boundary of delivered and exported energy
Heating energy
Cooling energy
Electricity for
lighting
Fuels
ENERGY
USE
BUILDING
TECHNICAL SYSTEMS
Energy use and production
System losses
and conversions
Electricity
ON SITE RENEWABLE
ENERGY W/O FUELS
District heat
District cooling
Electricity
Solar gains/
loads
Heat
transmission
ENERGY NEED
DELIVERED
ENERGY
EXPORTED
ENERGY
(renewable and
non-renewable)
Electricity for
appliances
Internal heat
gains/loads
RE generators
He
atin
g e
n.
Ele
ctr
icity
Co
olin
g e
n.
Energy use SB
Cooling en.
Heating en.Energy need SB
Building site boundary = system boundary of delivered and exported energy
Fuels
Electricity
District heat
District cooling
Electricity
DELIVERED
ENERGY
EXPORTED
ENERGY
(renewable and
non-renewable)
Building 1
Cooling en.
Heating en.
Building 2
Building n
SITE ENERGY
CENTRE
EXPERIENCE WITH LOW ENERGY
BUILDINGS
Per Heiselberg
ENERGY USE HIGHER THAN EXPECTED
Based on 230.000 single family houses with energy labelling. Preliminary results not yet validated or published
Reference: Kirsten Gram-Hanssen, SBi 2015
HOME FOR LIFE, LYSTRUP, DENMARK
Home for life – Energy Concept
Home for life – Energy balance
60
Energy production solar thermal
and solar cells
-33
Hot water and
heating
-14
Electricity
household
-8
Electricity
technique
Energy need and production from solar [kwh/m2/year]
EXPERIENCES RELATED TO ENERGY USE AND
PRODUCTION
THE MOST IMPORTANT DEVIATIONS:
• Energy use for heating higher than expected
• Electricity use for heat pump higher than expected
• Electricity use for control system higher than expected
• Energy use DHW lower than expected
• Electricity use for appliances and plug loads lower than expected.
• Production from solar thermal system as expected
• Production from PV as expected
Reference: Esbensen, 2012
1. Measured
2. As 1, corrected for weather
3. As 2, corrected for indoor temperature
4. As 3, corrected for lower person load
5. As 4, corrected for domestic electricity use
6. As 5, corrected for air tightness
7. As 6, corrected for less efficient heat recovery 8. As 7, corrected for use of solar shading 9. As 8, corrected for measuring equipment and screens 10. As 9, corrected for DHW use 11. As 10, corrected for efficiency of heat pump 12. Predicted energy use
Reference: Esbensen, 2012
RELATIVE IMPORTANCE OF DIFFERENT
ASPECTS
Reference: Esbensen, 2012
Overheating – l iving room
Reference: Esbensen
32%
24%
32%
10%
2%
Living year 1
58% 26%
13%
1% 2%
Living year 2
59% 20%
14%
1%
6%
Sleeping, year 1
66%
18%
13%
1% 2%
Sleeping, year 2
Reference: VELUX og Esbensen
IMPACT OF IMPROVED CONTROL AND OPERATION
WHY DO WE FACE THESE CHALLENGES IN
HIGH PERFORMANCE BUILDINGS?
IT IS NOT POSSIBLE TO REACH GOALS THROUGH MORE
• Envelope insulation, Building airtightness, Ventilation heat recovery,
WHICH ARE ROBUST TECHNOLOGIES WITHOUT USER INTERACTION
NEW MEASURES NEEDS TO BE INCLUDED
• Demand controlled ventilation
• Shading for solar energy control
• Shading for daylighting control
• Lighting control
• Window opening
ALL TECHNOLOGIES:
• Where performance is very sensitive to control
• Which involve different degree of user interaction
• Whose function and performance are difficult for users to understand
WHY DO WE FACE THESE CHALLENGES IN
HIGH PERFORMANCE BUILDINGS?
THE PRIMARY OBJECTIVE OF USERS IS FULLFILLMENT OF
THEIR NEEDS ( INDOOR ENVIRONMENT) AND THEY WILL
ALWAYS ADJUST CONTROLS ACCORDINGLY.
THIS OFTEN LEADS TO HIGHER ENERGY USE AND POORER
INDOOR ENVIRONMENT THAN EXPECTED.
AUTOMATIC CONTROL SHOULD BE BETTER ADAPTED TO THE
FULLFILMENT OF USER NEEDS
PER HEISELBERG
ENERGY EFFICIENT VENTILATION OF
HIGH PERFORMANCE BUILDINGS
ENERGY EFFICIENT VENTILATION OF
HIGH PERFORMANCE BUILDINGS
ENERGY DEMAND IN TYPICAL OFFICE
BUILDING
Condit ions U-value: 1,5 W/m²K, g-value: 0,60, Lt-value: 0,70
SFP: 2,1 kJ/m³
Light control: Manual
Thermal mass: Light
30 % window area in relation to floor area
Infiltration 0,3 h-1
Cooling Heating
Lighting Ventilation
Misc.
Energy demand distribution
Total energy demand 96 kWh/m²
ADDITIONAL CHALLENGES IN HIGH
PERFORMANCE BUILDINGS
The cu r ren t deve lopmen t towards nea r l y - zero energy bu i l d i n g s h ave l e ad to :
an i n c rea sed need for coo l i n g – no t on l y i n summer bu t a l l y e a r
• Increased potential for using the cooling potential of outdoor air
An reduc t ion o f E l e c t r i c i t y u se fo r a i r t r an spor t becomes i n c rea s i n g l y
impor t an t
• Increased use of natural/hybrid ventilation
• Distribution of cold air to rooms without creating discomfort
• Effective decentralized ventilation solutions
SIX DIFFERENT AIR DISTRIBUTION SYSTEMS
-Tested in the same geometry and with the same load
qo - ∆To Design Chart
WIDEX/WESSBERG A/S
WIDEX/WESSBERG A/S
SOLBJERGSKOLEN SOUTHWEST OF ÅRHUS
SYSTEM PRINCIPLE
DRAUGHT RISK
• Winter condition: supply air temperature -8 oC,
ACH =4
DR <20%
ISO 7730
VENTILATION SOLUTIONS
Building
Use Outdoor
Climate
Building
Design
IAQ
Thermal Comfort
Internal loads
Micro-
climate
Natural ventilation
Mechanical ventilation
Air Conditioning
Hybrid
ventilation
Occupant
Profile
RATIONALE FOR HYBRID VENTILATION
• HAS ACCESS TO BOTH VENTILATION MODES
IN ONE SYSTEM, EXPLOITS THE BENEFITS OF
EACH MODE AND CREATES NEW
OPPORTUNIT IES FOR FURTHER
OPTIMISATION AND IMPROVEMENT OF THE
OVERALL QUALITY OF VENTILATION.
• FULFILS THE HIGH REQUIREMENTS ON
INDOOR ENVIRONMENTAL PERFORMANCE
AND THE INCREASING NEED FOR ENERGY
SAVINGS AND SUSTAINABLE DEVELOPMENT.
• RESULTS IN H IGH USER SATISFACTION
BECAUSE OF THE HIGH DEGREE OF
INDIV IDUAL CONTROL AS WELL AS A DIRECT
AND V IS IBLE RESPONSE TO USER
INTERVENTIONS.
• OFFERS AN INTELLIGENT AND ADVANCED
VENTILATION SOLUTION FOR THE COMPLEX
BUILDING DEVELOPMENTS OF TODAY, THAT
IS USER TRANSPARENT AND SUSTAINABLE.
HYBRID VENTILATION STRATEGIES
Al te rna t i ng o r comb ined na tu ra l and mechan ica l ven t i la t ion
– This principle is based on a combination of two fully autonomous systems where the control strategy consists of switching between or combining both systems.
– It covers fx systems with natural ventilation in the intermediate seasons and mechanical ventilation during midsummer and/or midwinter or it covers systems with mechanical ventilation for workstations during occupied hours and natural ventilation for building and night cooling.
INSTITUTE OF DEVELOPMENT ECONOMIES
(JETRO), CHIBA, J
Courtesy of:
Dr. Tomoyki Chikamoto, Nikken Sekkei Ltd, Japan
Heat fromTask Zone
Supply fan unitfor Ambient Zone
Fresh air
Ambient Zone
Task Zone
CH C
EA (Exhaust Air)
OA (Outside Air)
Personal supply outlet for Task Zone(D air to human body)irect supply of fresh
Effective exhaustion ofheat and pollutant
CH COA
Personal AC system for Task Zone
Higher temp.upply jets
Under-floor AC systemfor Ambient Zone
20℃
22℃22℃
28℃26℃
High IAQ andthermal comfort
Pollutant fromTask Zone
26℃
30℃
HYBRID VENTILATION AND AIR CONDITIONING
SYSTEM
Automatically controlled window
- This opening is also used for smoke exhaust
opening in case of fire
Ambient
supply unit
Task supply unit
- Air volume and direction are
easily changed by each user
HYBRID VENTILATION AND AIR CONDITIONING
SYSTEM
Fresh air
Ambient Zone
Task Zone
CH C
EA (Exhaust Air)
OA (Outside Air)
CH COA
Air volume and direction are easily
changed by each user.
Task supply unit is detachable.
Ambient zone is controlled mildly by
central BA system for energy saving.
Task zone is controlled by each one’s
choice for human’s comfort.
Warm air
Cool air
CONTROL OF HYBRID VENTILATION AND AIR
CONDITIONING SYSTEM
HYBRID VENTILATION STRATEGIES
STACK AND WIND SUPPORTED MECHANICAL
VENTILATION
– This principle is based on a mechanical ventilation
system, which makes optimal use of natural driving
forces.
– It covers mechanical ventilation systems with very
small pressure losses where natural driving forces
can account for a considerable part of the necessary
pressure difference.
N
M
Mediå School, Grong, Norway
Courtesy of:
Professor Per Olaf Tjelflaat, Norwegian University for
Science and Technology, Trondheim, Norway
AIR SUPPLY SYSTEM
AIR EXHAUST SYSTEM
Mediå School, Grong, Norway
LOW PRESSURE LOSS IN SYSTEM
• VENTILATION SUPPLY ABOUT 35 PA
– Filter about 15 pa
– Heat recovery about 10 pa
– Heating about 5 pa
• VENTILATION EXHAUST ABOUT 20 PA
– Heat recovery about 12 pa
TOTAL PRESSURE LOSS WINTER ABOUT 55 PA
TOTAL PRESSURE LOSS SUMMER ABOUT 28 PA
PRESSURE LOSS SUMMER (WITHOUT FILTER) ABOUT 13 PA
Energy efficient Heating and
Cooling of buildings
• Low temperature Heating-High Temperature Cooling
• Water based systems
• Radiant heating and cooling ceiling panels
• Thermo Active Building Systems (TABS)
• Chilled beams
• Floor heating and cooling
Low-Temperature heating
High-Temperature Cooling
• Heat exchange through large surfaces
(floor, ceiling, walls)
• Supply water temperatures:
– Heating: 25 – 40 °C
– Cooling: 16 – 23 °C (temperature limited by
dew-point to avoid condensation)
• Wide range of systems, solutions both for
residential and non-residential buildings
74
Sustainability
75
• Higher efficiency of boilers and chillers
• Lower distribution looses
• Better use of renewable energy sources
– Ground heat exchangers
– Waste heat from processes
– Dry coolers
– Heat pumps
• Low energy consumption for
circulation
• Low exergy
CONCEPTS OF RADIANT HEATING AND
COOLING SYSTEMS
• Minimum 50% heat exchange by radiation
• Heating - cooling panels
• Surface systems
• Embedded systems
• Most recent development is the increasing
application world wide.
Suspended cooled ceilings
System types
Water as the heat carrier
Heat exchange is > 50% radiant
Different installation concepts
(thermally coupled or insulated form the building structure)
78
THERMO ACTIVE BUILDING SYSTEMS (TABS)
Trend started in nineties in Switzerland, typically used in Europe
Suitable primarily for sensible cooling and for base heating
Installed in the centre of concrete slab between the reinforcements
Diameter of the pipes varies between 17 and 20 mm
The distance between pipes is within the range 150 - 200 mm
Installed during the main building construction with prefabricated slabs.
Reinforcement
Floor
Concrete
Pipes
Window
Room
Room
Concept of
Thermo Active Building Systems
Concept of
Thermo Active Building Systems (TABS) EXAMPLE OF INTERNAL CONDITIONS WITH THERMAL SLAB
20
21
22
23
24
25
26
27
28
29
30
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.0
0
11.0
0
12.0
0
13.0
0
14.0
0
15.0
0
16.0
0
17.0
0
18.0
0
19.0
0
20.0
0
21.0
0
22.0
0
23.0
00.
00
TE
MP
ER
AT
UR
E [
°C]
-1
-0.5
0
0.5
1
PR
ED
ICT
ED
ME
AN
VO
TE
T floor
PMV
T airT mr
T water return
T ceiling
COMBINATION WITH LOW ENERGY
SOURCES
UPONOR Corporation (2010)
Heating supply temp. : 25 - 40°C
heat pumps
condensing boiler
ground coupling
waste heat
solar energy
Cooling supply temp. : 16 - 23°C
reversible heat pump
ground coupling
free cooling
air cooled chillers 82
Day
Night
Cooling method
Ground water
Geothermal
heat/coolth
Night air
Cooling unit
Additional benefits – large atriums and
foyers
83
The under-floor cooling system directly removes solar heat gains
Minimum of such gains influences air temperature
Comfortable floor surface temperature is maintained at the same time
Airport Bangkok
Airport Bangkok
June 30 2008
Terminal building
Balanced Office Building
Aachen, Germany
• Gross floor area 2,151 m²
• 4 storeys
• Efficiently insulated external envelope
• Ground-coupled heating and cooling with TABS
• Ventilation system with heat recovery
• Daylight-controlled lighting
• Rainwater collection for use in toilet flushing
Energy concept
cooling period
0
5000
10000
15000
20000
25000
30000
35000
Heizung Kühlung Lüftung Beleuchtung Pumpen Warmwasser Summe
Yearl
y e
nerg
ie c
osts
[€/m
²a]
Bestand
BOB.1
Energy efficiency
94 % energy saving compared with conventional
cooling
60 % energy saving for lighting by daylight
steering
The need of energy for heating, cooling, air-
ventilation lighting and warm water is 27,8
kWh/m² per year
Energy costs per m², per year: 2,7 EUR,
per month 22,5 Cent
Office Building in Madrid, Spainain
91
16 000 m2
Natural & Mechanical ventilation
External solar shading & green
facade
TABS combinned with free cooling
(covers 40-50 kWh/m2)
(kWh/m²y) Actual CTE - MADRID %
Heating + DHW 27,35 77,00 -64,5
Cooling 12,58 85,00 -85,2
Lighting 11,37 34,00 -66,6
Total 51,30 196,00 -73,8
Energy use
Office Building in Madrid, Spain
92
Chilled Beams Water based distribution
Chilled Beams
Chilled Beams
Water based distribution
Low Exergy Hydronic Radiant Heating and Cooling
Why?
• Water based systems
• Low temperature heating - High temperature cooling
• More economical to move heat by water:
– Greater heat capacity than air
– Much smaller diameter pipes than air-ducts
– Electrical consumption for circulation pump is lower than for fans
• Lower noise level
• Less risk for draught
• Lower building height for TABS
• Higher efficiency of energy plant
• But
– Reduced capacity?
– Acoustic?
– Latent load?
VENTILATIVE COOLING
P E R H E I S E L B E R G
D E P A R T M E N T O F C I V I L E N G I N E E R I N G
DEFINITION OF VENTILATIVE COOLING
VENTILATIVE COOLING IS APPLICATION (DISTRIBUTION IN
T IME AND SPACE) OF VENTILATION AIR FLOW TO REDUCE
COOLING LOADS IN BUILDINGS
VENTILATIVE COOLING UTILIZES THE COOLING AND
THERMAL PERCEPTION POTENTIAL (HIGHER AIR
VELOCITIES) OF OUTDOOR AIR
IN VENTILATIVE COOLING THE AIR DRIVING FORCE CAN BE
NATURAL, MECHANICAL OR A COMBINATION
VENTILATIVE COOLING IS A SOLUTION
THE DEVELOPMENT TOWARDS ”NEAR ZERO ENERGY BUILDINGS ”
HAS RESULTED IN AN INCREASED NEED FOR COOLING – NOT ONLY
IN SUMMER BUT MOST OF THE YEAR!
VENTILATIVE COOLING CAN BE AN ATTRACTIVE AND ENERGY
EFFICIENT PASSIVE SOLUTION TO REDUCE COOLING AND AVOID
OVERHEATING.
• Ventilation is already present in most buildings through mechanical and/or
natural systems using opening of windows
• Ventilative cooling can both remove excess heat gains as well as increase air
velocities and thereby widen the thermal comfort range.
• The possibilities of utilizing the free cooling potential of low temperature
outdoor air increases considerably as cooling becomes a need not only in the
summer period.
POTENTIAL AND LIMITATIONS
OUTDOOR CLIMATE POTENTIAL
• Outdoor temperature lower than the thermal comfort limit in large part of the
year in many locations
• Especially night temperatures are below comfort limits
• Natural systems can provide “zero” energy cooling in many buildings
L IMITATIONS
• Temperature increase due to climate change might reduce potential
• Peak summer conditions and periods with high humidity reduce the potential
• An urban location might reduce cooling potential (heat island) as well as
natural driving forces (higher temperature and lower wind speed). Elevated
noise and pollutions levels are also present in urban environments
• Building design, fire regulations, security are issues that might decrease the
use of natural systems
• High energy use for air transport limit the potential for use of mechanical
systems
Annex 62 Ventilative Cooling
IEA EBC Annex 62
Ventilative Cooling
Annex 62 Ventilative Cooling
Annex Objectives
• To analyse, develop and evaluate suitable methods and tools for
prediction of cooling need, ventilative cooling performance and risk
of overheating in buildings that are suitable for design purposes.
• To give guidelines for integration of ventilative cooling in energy
performance calculation methods and regulations including
specification and verification of key performance indicators.
• To extend the boundaries of existing ventilation solutions and their
control strategies and to develop recommendations for flexible and
reliable ventilative cooling solutions that can create comfortable
conditions under a wide range of climatic conditions.
• To demonstrate the performance of ventilative cooling solutions
through analysis and evaluation of well-documented case studies.
Annex 62 Ventilative Cooling
Annex Outcome
• Guidelines for energy-efficient reduction of the risk of overheating by ventilative cooling
• Guidelines for ventilative cooling design and operation in residential and commercial buildings
• Recommendation for integration of ventilative cooling in legislation, standards, design briefs as well as on energy performance calculation and verification methods
• New ventilative cooling solutions including their control strategies as well as improvement of capacity of existing systems
• Documented performance of ventilative cooling systems in case studies
Annex 62 Ventilative Cooling
Annex Leadership
• Participating countries – Austria, Belgium, China, Denmark, Ireland, Italy, Japan, Netherlands,
Norway, Portugal, Switzerland, UK, USA
• Operating Agent: – Denmark, represented by Per Heiselberg, Aalborg University
• Subtask A: – Leader: Switzerland, represented by Fourentzos Flourentzou, ESTIA
– Co-leader: Italy, represented by Annamaria Belleri, EURAC
• Subtask B: – Leader: Austria, represented by Peter Holzer, IBRI
– Co-leader: Denmark, represented by Theofanis Psomas, AAU
• Subtask C: – Leader: China, represented by Guoqiang Zhang, Hunan University
– Co-leader: Ireland, represented by Paul O’Sullivan, CIT
DIFFUSE CEILING VENTILATION
P E R H E I S E L B E R G
D E P A R T M E N T O F C I V I L E N G I N E E R I N G
COOLING IN OFFICES AND EDUCATIONAL
BUILDINGS
WITH HIGH INSULATION AND A IR T IGHTNESS LEVELS ALWAYS A
COOLING NEED DURING OCCUPIED HOURS EVEN IN THE WINTER
SEASON
COOLING IS NOT A NEW TECHNOLOGY, BUT THE NEED FOR
COOLING IS INCREASING AND MORE EFFICIENT SYSTEMS HAVE TO
BE DEVELOPED TO FULFILL FUTURE ENERGY REQUIREMENTS
APPLICATION OF THE FREE COOLING POTENTIAL OF OUTDOOR AIR
IS WIDELY USED IN MECHANICAL VENTILATION SYSTEMS, BUT
HIGH A IR FLOW RATES ARE NEEDED IN WINTER BECAUSE OF
DRAUGHT RISK LEADING TO RELATIVELY HIGH ENERGY USE FOR
A IR TRANSPORT
WHAT IS DIFFUSE CEILING VENTILATION
THE SPACE ABOVE A SUSPENDED CEIL ING IS USED AS A PLENUM
AND FRESH A IR IS SUPPLIED TO THE OCCUPIED ZONE THROUGH
PERFORATED SUSPENDED CEIL ING.
THE PRINCIPLE
Rockfon / Troldtekt ceiling
Ecophon ceiling
Fully diffuse ceiling
SIX DIFFERENT AIR DISTRIBUTION SYSTEMS
-Tested in the same geometry and with the same load
QO - ∆TO DESIGN CHART
WIDEX/WESSBERG A/S
WIDEX/WESSBERG A/S
SOLBJERGSKOLEN SOUTHWEST OF ÅRHUS
SYSTEM PRINCIPLE
DRAUGHT RISK
• Winter condition: supply air temperature -8 oC, ACH =4
DR <20% ISO 7730
HEAT LOAD LOCATION
Evenly distributed Center
Front side Back side
VELOCITY DISTRIBUTION
DRAUGHT RISK
0
2
4
6
8
10
12
14
16
18
20
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
DR
[%
]
Distance from inlet [m]
Evenly Center
Front side Back side
ROOM HEIGHT
2.335 m 3.0 m 4.0 m
VELOCITY DISTRIBUTION
2.335 m 3.0 m 4.0 m
DRAUGHT RISK
0
2
4
6
8
10
12
14
16
18
20
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
DR
[%
]
Distance from inlet [m]
2.335 m
3.0 m
4.0 m
DIFFUSE CEILING OPENING AREA
100% DF 18% DF
VELOCITY DISTRIBUTION
100% DF 18% DF
DRAUGHT RISK
0
2
4
6
8
10
12
14
16
18
20
0 1 2 3 4 5
DR
[%
]
Distance from inlet [m]
0.1 m
0.6 m
1.1 m
1.7 m
0
2
4
6
8
10
12
14
16
18
20
0 1 2 3 4 5
DR
[%
] Distance from inlet [m]
0.1 m
0.6 m
1.1 m
1.7 m
100% DF 18% DF
CONCLUSION
Low draught risk in the occupied zone even, when supplying air at
temperatures below 0Co
Air distribution and draught risk dependent on heat load location, ceiling
height, area and location of supply.
Very low vertical temperature gradient in the room with diffuse celling
supply
Low radiant temperature asymmetry and no clear radiation cooling
potential of diffuse ceiling, due to low conductivity
Very low pressure drop across diffuse ceiling (less than 5 Pa)